Facile, high yield ultrasound mediated protocol for ZnO hierarchical structures synthesis: Formation mechanism, optical and photocatalytic properties.

Hierarchical flowers-like zinc oxide structures have been successfully obtained by a simple and fast ultrasound-assisted method performed in a ordinary ultrasonic bath using an ammonia solution and zinc acetate, in the absence of any surfactant or template. The composition, structure, crystallinity, morphology and optical properties of the materials obtained at different ultrasound irradiation times were characterized by infrared, UV-Vis and photoluminescence spectroscopy, X-ray diffraction, scanning and transmission electron microscopy investigations. It was proved that the ultrasound irradiation time manipulates both the defect content (implicit the photoluminescent properties) and morphology of the ZnO materials: shorter irradiation times leads to the synthesis of high-defected ZnO structures of flower morphology with triangular-shaped petals, while higher irradiation times favours the formation of low-defected ZnO structures with tipped rod-like petals.

A general, eco-friendly synthesis procedure of self-assembled ZnO-based materials with multifunctional properties.

A bioinspired one-pot approach for the synthesis of ZnO-carbohydrate hierarchical architectures was developed. The synergy between a saccharide (mono-, di- or polysaccharide) that contains d-glucose units and triethanolamine is the key parameter of the synthetic methodology. The morphology of the ZnO composites is dictated by the saccharide used, and rod, spindle, solid and hollow spherical-like ZnO structures are obtained by varying the carbohydrate.

Biopolymer starch mediated synthetic route of multi-spheres and donut ZnO structures.

A starch-assisted synthetic methodology of multispheres ZnO-starch biocomposites was developed. An additional thermal processing of the ZnO-starch composites induces the formation of ZnO with donut-like morphology. The synthesis of single-phase zinc oxide with a spherical morphology is conditioned by the presence of starch, which acts as template, stabilizing/capping agent.